squash! Define __getattribute__() instead of __getattr__() on slotted classes with cached properties

In tests, we replace most custom `__getattr__()` definitions by
equivalent `__getattribute__()` ones, except in regression tests where
`__getattr__()` is explicitly involved. Also, in
test_slots_with_multiple_cached_property_subclasses_works(), we replace
the `if hasattr(super(), "__getattr__"):` by a `try:`/`except
AttributeError:` as using `hasattr(..., "__getattribute__")` would be
meaningless since `__getattribute__()` is always defined.

Author: dlax

tests/test_slots.py

@@ -786,7 +786,7 @@ def f(self) -> int:
 
 
 @pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
-def test_slots_cached_property_with_empty_getattr_raises_attribute_error_of_requested():
+def test_slots_cached_property_with_empty_getattribute_raises_attribute_error_of_requested():
     """
     Ensures error information is not lost.
     """
@@ -809,8 +809,8 @@ def f(self):
 @pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
 def test_slots_cached_property_raising_attributeerror():
     """
-    Ensures AttributeError raised by a property is preserved by __getattr__()
-    implementation.
+    Ensures AttributeError raised by a property is preserved by
+    __getattribute__() implementation.
 
     Regression test for issue https://github.com/python-attrs/attrs/issues/1230
     """
@@ -846,9 +846,9 @@ def q(self):
 
 
 @pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
-def test_slots_cached_property_with_getattr_calls_getattr_for_missing_attributes():
+def test_slots_cached_property_with_getattribute_calls_getattr_for_missing_attributes():
     """
-    Ensure __getattr__ implementation is maintained for non cached_properties.
+    Ensure __getattribute__ implementation is maintained for non cached_properties.
     """
 
     @attr.s(slots=True)
@@ -859,7 +859,7 @@ class A:
         def f(self):
             return self.x
 
-        def __getattr__(self, item):
+        def __getattribute__(self, item):
             return item
 
     a = A(1)
@@ -868,16 +868,16 @@ def __getattr__(self, item):
 
 
 @pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
-def test_slots_getattr_in_superclass__is_called_for_missing_attributes_when_cached_property_present():
+def test_slots_getattribute_in_superclass__is_called_for_missing_attributes_when_cached_property_present():
     """
-    Ensure __getattr__ implementation is maintained in subclass.
+    Ensure __getattribute__ implementation is maintained in subclass.
     """
 
     @attr.s(slots=True)
     class A:
         x = attr.ib()
 
-        def __getattr__(self, item):
+        def __getattribute__(self, item):
             return item
 
     @attr.s(slots=True)
@@ -949,9 +949,9 @@ def __getattr__(self, item: str) -> str:
 
 
 @pytest.mark.skipif(not PY_3_8_PLUS, reason="cached_property is 3.8+")
-def test_slots_getattr_in_subclass_gets_superclass_cached_property():
+def test_slots_getattribute_in_subclass_gets_superclass_cached_property():
     """
-    Ensure super() in __getattr__ is not broken through cached_property re-write.
+    Ensure super() in __getattribute__ is not broken through cached_property re-write.
     """
 
     @attr.s(slots=True)
@@ -962,7 +962,7 @@ class A:
         def f(self):
             return self.x
 
-        def __getattr__(self, item):
+        def __getattribute__(self, item):
             return item
 
     @attr.s(slots=True)
@@ -971,8 +971,8 @@ class B(A):
         def g(self):
             return self.x
 
-        def __getattr__(self, item):
-            return super().__getattr__(item)
+        def __getattribute__(self, item):
+            return super().__getattribute__(item)
 
     b = B(1)
     assert b.f == 1
@@ -1023,10 +1023,11 @@ class B:
         def g(self):
             return self.x * 2
 
-        def __getattr__(self, item):
-            if hasattr(super(), "__getattr__"):
-                return super().__getattr__(item)
-            return item
+        def __getattribute__(self, item):
+            try:
+                return super().__getattribute__(item)
+            except AttributeError:
+                return item
 
     @attr.s(slots=True)
     class AB(A, B):